I like Emerson as much as I do any cranky old lefty who'll tweak the Kos wing of the Democratic party* (see: Riley, Doghouse and Sawicky, Max) but I think he's reaching a bit there.
Maliki had plenty of reason to push the Basra operation himself: local elections are coming up this year and the Sadrist machinery provides a big popular base for a political rival. It's in his interest to hit the Mehdi Army and its associated pseudo-government operations, whether he's trying to build the Iraqi Army in a force loyal to him, get jobs for the Badr brigade, or just generally kneecap Sadr.
I don't think a physical visit is really dispositive in the digital age. Maliki has a phone and Cheney presumably has his number. There are enough people in the executive branch who don't like Cheney that there should be some leaks if he gets up to anything particularly egregious.
Emerson's second point about Kagan is right, but it's not new. If supporting the war in general can't cost someone their seat at the pundit table, being specifically wrong about something war-related five years into it won't do the trick. At least
Joe Klein is taking shots at the Kagans, which is just a couple steps removed from David Broder doing it.
As for the Democratic candidates, they say they want the US out and at least Obama has said the US shouldn't train Iraqi troops if they're just ethnic or partisan militias with official cover. I'm not sure what he wants from them that he isn't getting.
*Though I recognize that the Kos wing is doing a lot of the actual grunt work in putting Democrats in office, which is generally a good thing. There's just a tendency among them to lose sight of why politics are important, and to make convenient criticisms of the GOP (this war was badly planned) over philosophical ones (almost all war is horrible).
